I've been in similar situations but fortunately not very many. I used to get angry and pissed off when things like this would happen and then I realized that my getting angered didn't really solve anything and I wasn't "out of pocket" or anything either. I was just worked up through the anticipation of spending a relatively small amount of time with a woman I probably would never get to spend time with under any other means.
Once I realized this, the "no shows" stopped bothering me and I just stopped trying to spend time with the provider(s) in question. There have been some providers I've seen in the past, with whom I've had some great experiences who (for whatever reason) don't return phone calls or e-mail messages anymore and rather than get miffed and slam them on public boards (I'm not saying ANYONE is slamming anyone in this thread), I just stopped trying to see them. It's true that I'm missing out on their company but the amount of time we spent together was so short *anyway* that it really wasn't worth the stress I was causing myself by getting all worked up over it.
To me, the "hobby" is a luxury and not a necessity. If it were a necessity, I would be living out of a cardboard box and dodging the bill collectors.
Spending time with some great ladies and having some awesome experiences (which I truly cherish and treasure) is something I like doing and want to do, but not something that I *need* to do. So, for me it's not that big of an issue if a lady flakes out on me. I've been in situations where I've taken time off from work mid-afternoon, scheduled vacation days so I would have time to arrange for an room for an outcall, etc., and have been in the "waiting mode" for hours on end only to learn that the lady didn't show.
In fact, earlier this year I flew to Las Vegas and had a nice room at the Tropicana for the *sole* purpose of meeting a provider. A week before our appt, I sent her e-mail letting her know she had not given me her phone number and asked her to let me know how I was to contact her once in Las Vegas. Then the day before the appt, I sent her e-mail letting her know I didn't have her number and sent her my wireless number asking her to call me. Then on travel day, I sent another e-mail message to her with the same information (didn't have her number and sent my wireless number). I did end up hearing from her at mid-night that night and she called me expressing her concern that I had not contacted her about the appt she thought we had booked for that night. I told her about the e-mail messages I sent and her NOT giving me her number and she was apologetic about not checking her e-mail any sooner but that didn't change the fact I had spent the money to uphold my end of the arrangement, which would NOT be refunded to me. I fly back home the next day. After a while, my hopes that she would call me while I was waiting changed to a brief disappointment and then to an "oh well, c'est la vie" and I went to bed. When she called around midnight, she woke me up. 
I don't hold any bad feelings toward her or anything but I'm not enthuisastic about trying to see her given what happened the first time. There are far too many other ladies, and really GREAT ones at that, out there for me to get worked up over this kind of experience. If it turns out to be a repetitious thing with various other providers, I'll stop travelling to them and will admire their beauty and imagine my experience with them through online avenues and reviews (respectively).
With regard to the first rant, I think a number of ladies do understand that there are things the guys must go through to prepare, just as the ladies do, but there are some who just don't care.
The one thing that I find most interesting is the issue of time. Some providers I've seen insist that I show up *exactly* at the time of the appt and I should not show up early (which I can definitely understand especially after hearing some stories of some truly idiotic things some guys have done when they show up early) and not to be too late (of course). Today, when I see a provider who has an arrival time requirement I always look at the clock she has in the room to see what time it shows and compare it to the time on my wireless phone to see what the delta is, if any. I know some ladies adjust the time into the future by some number of minutes (for whatever reasons) but I have no way of knowing if any given lady does it or not. Some providers have commented on my being a "little late" when my wireless phone shows I'm right on time, give or take 60 secs.
Take care...
Peace...